High-strength aluminum-copper alloy and preparation method and application thereof

Abstract

The invention discloses a high-strength aluminum-copper alloy and a preparation method and application thereof, and belongs to the field of aluminum-copper alloy casting. According to the technical scheme, the aluminum alloy comprises the following raw materials in percentage by mass: 3.5%-5.5% of Cu, 0.6%-1.0% of Mn, 0.2%-0.4% of Ti, 0.3%-0.5% of Sc, 0.2%-0.4% of V, 0.2%-0.4% of Ce, 0.1%-0.3% of Zr and the balance of Al and inevitable impurities. By optimizing the components and adding granular compound elements such as Ti, V, Zr, Mn and the like, precipitated phases such as Al3Ti, Al3Zr, Al6Mn and the like can be formed in the alloy melt and solidification process, dislocation motion can be inhibited, grain boundary slippage can be hindered, a small amount of Ti and Zr phases which do not participate in reaction are also distributed in a matrix in a small rod form, rare earth elements Sc and Ce are added, and therefore the mechanical property of the alloy is improved. Particle aggregation of a precipitated phase can be effectively inhibited, the effect of refining grains is achieved, the size of the precipitated phase can be reduced to a certain degree, a blocky alloy phase is changed into a short strip shape or a short rod shape, stress concentration is reduced, then the splitting effect on a matrix is reduced, and the comprehensive mechanical property of the material is improved.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-copper alloy casting technology, and particularly relates to a high-strength aluminum-copper alloy, its preparation method and application. Background Technology

[0002] With the rapid development of military equipment, aerospace, and other fields, and the increasing prominence of current energy and environmental issues, new challenges and higher requirements have been placed on the high-temperature performance and lightweight requirements of products. Structural materials, while meeting mechanical performance requirements, will also need to be lightweight and heat-resistant, becoming a key focus of new material research and development. To cope with the complex environment and deep-sea combat requirements of large naval equipment and achieve precision strike capabilities against deep-sea targets, the demands on the shell's ability to withstand external hydraulic pressure and its own strength have increased dramatically. This places higher demands on the high strength and toughness of materials. Aluminum-copper alloys, with strength even reaching that of steel and excellent machinability, have promising applications in aerospace, military, and civilian products, providing more opportunities and possibilities for achieving lightweighting, low cost, and improved product reliability.

[0003] Aluminum-copper alloys are typical age-hardening alloys, with their strengthening mechanism primarily stemming from the pinning effect of precipitated phase particles on dislocations. Conventional aluminum-copper alloys exhibit high mechanical properties at room temperature, but under high-temperature conditions, the rapid coarsening of the precipitated phase leads to a significant decrease in material strength. Furthermore, high-strength, heat-resistant cast aluminum alloys possess strong dendritic solidification characteristics and a wide liquidus-solidus temperature range (i.e., a broad solidification range). This results in poor fluidity during casting, a large shrinkage rate from liquid to solid, difficulty in achieving sequential solidification, and high thickness sensitivity. Consequently, castings are prone to defects such as shrinkage porosity, cracks, segregation, and hot cracking during the forming process, severely impacting the internal quality and mechanical properties of the cast products. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is that the high-temperature strength of existing aluminum-copper alloys is greatly reduced, and casting defects such as shrinkage porosity, cracks, segregation and hot cracks are easily generated during the forming process. By optimizing the alloy composition and casting process, the fluidity of aluminum-copper alloy and the solidification sequence during solidification are effectively improved, and a high-strength aluminum-copper alloy with excellent mechanical properties under high temperature conditions, as well as its preparation method and application, are obtained.

[0005] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: This invention provides a high-strength aluminum-copper alloy, wherein, by mass percentage, its raw materials include Cu 3.5%-5.5%, Mn 0.6%-1.0%, Ti 0.2%-0.4%, Sc 0.3%-0.5%, V 0.2%-0.4%, Ce 0.2%-0.4%, Zr 0.1%-0.3%, with the balance being Al and unavoidable impurities.

[0006] Preferably, the high-strength aluminum-copper alloy has a yield strength greater than 420 MPa, a tensile strength greater than 490 MPa, and an elongation greater than 5% at room temperature; and a yield strength greater than 250 MPa, a tensile strength greater than 315 MPa, and an elongation greater than 9.5% at a high temperature of 200℃.

[0007] Another aspect of the present invention provides a method for preparing the above-mentioned high-strength aluminum-copper alloy, comprising a smelting step, wherein the smelting step includes: Aluminum ingots, Cu-containing raw materials, Mn-containing raw materials, Ti-containing raw materials, Sc-containing raw materials, V-containing raw materials, Ce-containing raw materials, and Zr-containing raw materials are added to a furnace and heated to melt. After modification and refinement treatment, ultrasonic treatment is performed. After standing, differential pressure casting is performed to obtain the ingot.

[0008] Preferably, the smelting step includes: Aluminum ingots, Cu-containing raw materials, Mn-containing raw materials, Ti-containing raw materials, Sc-containing raw materials, V-containing raw materials, Ce-containing raw materials, and Zr-containing raw materials are added to a furnace and heated to melt. The temperature is raised to 730-740℃, and the mixture is stirred for 5-10 minutes before adding a modifier for modification treatment. Then, the temperature is raised to 740-750℃, and argon gas is used for rotary degassing. After degassing, the mixture is allowed to stand for 3-5 minutes, and after removing the slag, a refining agent is added for refining treatment. The mixture is then stirred for 1-5 minutes, allowed to stand for 3-5 minutes, and then ultrasonically stirred for 10-15 minutes. After standing for 10-20 minutes, differential pressure casting is performed at 730-740℃ to obtain the ingot.

[0009] Preferably, the frequency of the ultrasonic treatment is 15-30Hz.

[0010] Preferably, the modifier is an AlSr10 master alloy and the refining agent is an AlTi5B1 master alloy.

[0011] Preferably, the Cu-containing raw material is an AlCu master alloy and / or pure copper; The Mn-containing raw material is an AlMn master alloy and / or pure manganese; The Ti-containing raw material is an Al-Ti master alloy and / or pure titanium; The Sc-containing raw material is an Al-Sc master alloy and / or pure scandium; The V-containing raw material is an Al-V master alloy and / or pure vanadium; The Ce-containing raw material is an Al-Ce master alloy and / or pure cerium; The Zr-containing raw material is an Al-Zr master alloy and / or pure zirconium.

[0012] Preferably, the Cu-containing raw material is an Al50Cu master alloy; the Mn-containing raw material is an AlMn10 master alloy; the Ti-containing raw material is an AlTi4 master alloy; the Sc-containing raw material is an AlSc2 master alloy; the V-containing raw material is an AlV4 master alloy; the Ce-containing raw material is an AlCe10 master alloy; and the Zr-containing raw material is an AlZr4 master alloy.

[0013] Preferably, the preparation method further includes solution treatment and aging treatment of the ingot; The solution treatment conditions are as follows: the solution treatment temperature is 530-540℃, the solution treatment time is 10-20h, and then quenching is performed in water at 40-60℃. After quenching, leave the product in air for 12-25 hours, then perform an aging treatment. The conditions for the aging treatment are: aging temperature of 150-160℃ and aging time of 6-10h.

[0014] In another aspect, the present invention provides the application of the above-mentioned high-strength aluminum-copper alloy in the field of aviation or naval equipment.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a high-strength aluminum-copper alloy. Through composition optimization, in addition to the basic alloying elements Al and Cu, it also includes particulate compounds such as Ti, V, Zr, and Mn. During the alloy melt and solidification process, precipitates such as Al3Ti, Al3Zr, and Al6Mn are formed. These precipitates can suppress dislocation movement and hinder grain boundary slip; in particular, fine precipitates play a crucial role in the material's strength. A small amount of unreacted Ti and Zr phases are also distributed in the matrix in the form of small rods. The addition of rare earth elements Sc and Ce not only effectively inhibits the agglomeration of precipitates and increases the nucleation rate and nucleation rate of heterogeneous nucleation, thus refining the grains, but also improves the compositional supercooling of the high-strength aluminum-copper alloy melt. During heat treatment, the rare earth elements refine and even change the morphology of the precipitates, and to some extent reduce their size, transforming bulk alloy phases into short strips or rods. This reduces stress concentration and thus reduces the cutting effect on the matrix, effectively improving the microstructure refinement and enhancing the overall mechanical properties of the material. Furthermore, in addition to forming a large amount of AlCu(Sc, Ce) phase during solidification, the small amount of dispersed ternary phase AB(Ti) in the alloy is also reduced.x Zr 1-x It will undergo a phase transition, transforming into Al3(Sc) x Ti y Zr 1-x-y Furthermore, the number of dispersed phases will increase with the increase of rare earth elements, while the increase in the number of precipitated phases can promote the nucleation of θ' phase during aging, thereby enhancing the aging strengthening effect of the alloy.

[0016] This invention provides a method for preparing a high-strength aluminum-copper alloy. Ultrasonic treatment is applied to the melt, generating an alternating high-frequency sound pressure field within the melt. This sound pressure field causes air bubbles to form. These cavitation bubbles, created by the sound pressure, are subsequently subjected to intense compression and collapse. The collapse generates localized high-pressure shock waves that melt or even shatter growing crystals, inhibiting the growth of coarse grains. Simultaneously, these crystal fragments, under the influence of ultrasonic flow, accompany the melt and eventually become uniformly distributed within the melt, increasing the number of nuclei. This method enhances the convection of hot melt fluids between melt components, reduces the temperature gradient between different parts of the melt, and makes the temperature field more uniform, effectively reducing defects such as porosity, gas bubbles, and compositional segregation. Attached Figure Description

[0017] Figure 1 The images show the as-cast microstructure of the sample prepared in this example and the microstructure after T6 treatment. Figure 2 Microscopic images of the sample prepared for Comparative Example 1 after T6 treatment; Figure 3 Microscopic images of the sample prepared for Comparative Example 2 after T6 treatment; Figure 4 Microscopic images of the sample prepared for Comparative Example 5 after T6 treatment. Detailed Implementation

[0018] The technical solutions in specific embodiments of the present invention will now be described in detail and completely with reference to the accompanying drawings. Obviously, the described embodiments are merely some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0019] This invention provides a high-strength aluminum-copper alloy, the raw materials of which, by mass percentage, include Cu 3.5%-5.5%, Mn 0.6%-1.0%, Ti 0.2%-0.4%, Sc 0.3%-0.5%, V 0.2%-0.4%, Ce 0.2%-0.4%, Zr 0.1%-0.3%, with the balance being Al and unavoidable impurities.

[0020] It should be noted that aluminum-copper alloys are typical age-hardening alloys, and their strengthening mechanism mainly comes from the pinning effect of precipitated phase particles on dislocations. Conventional aluminum-copper alloys have high mechanical properties at room temperature, but under high-temperature conditions, the strength of the material decreases significantly due to the rapid coarsening of the precipitated phase. At the same time, high-strength heat-resistant cast aluminum alloys have strong dendritic solidification characteristics and a large liquidus-solidus temperature range (i.e., a wide solidification range), resulting in poor fluidity of the alloy during casting, large shrinkage from liquid to solid, difficulty in achieving sequential solidification, and high thickness sensitivity. Castings are prone to casting defects such as shrinkage porosity, cracks, segregation, and hot cracks during the forming process, which seriously affects the internal quality and mechanical properties of the casting products.

[0021] To address the above problems, this invention optimizes the composition, incorporating not only the basic alloying elements Al and Cu, but also particulate compounds such as Ti, V, Zr, and Mn. During smelting, Ti generates numerous fine Al3Ti particles, which act as α-Al heterogeneous nucleation sites, thus refining the grains and improving mechanical properties and machinability. V and Zr form dispersed strengthening phases, enhancing the alloy's high-temperature strength and thermal stability, inhibiting recrystallization, and extending its service life. Mn helps refine the grains, strengthen the solid solution, inhibit the formation of harmful phases, and improve the alloy's corrosion resistance and mechanical properties. Adding a certain amount of Ce and Sc to aluminum-copper alloys, in addition to alloying elements such as Ti, Zr, Mn, and V, mainly plays the following roles: First, the low-melting-point eutectic formed by rare earth elements and aluminum has good fluidity, reducing the tendency of the alloy to shrinkage porosity and hot cracking, and improving the casting performance of aluminum alloys; Second, adding rare earth elements can refine the grains of aluminum alloys, improving the strength, toughness, machinability, and corrosion resistance of aluminum alloy parts; Third, the addition of rare earth elements causes the formation of second-phase dispersed particles with high melting point, good thermal stability, low diffusion coefficient, and large volume fraction in aluminum alloys, improving the high-temperature tensile properties and creep strength of aluminum alloys. The addition of rare earth element Ce to aluminum-copper alloys has several beneficial effects. Firstly, Ce's high reactivity leads to the formation of fine, layered structures within the microstructure. This structure effectively disperses the agglomeration of granular phases, resulting in a finer microstructure, reduced stress concentration within the casting microstructure, and consequently, improved hot cracking tendency and increased matrix strength. Secondly, the addition of Ce narrows the solidification temperature range, helping to reduce grain growth rate and thus limiting grain growth. Adding Sc to Ce-containing aluminum-copper alloys not only controls the formation of the micron-scale AlCe eutectic phase but also allows for the formation of nano-sized Al₂Cu precipitates through subsequent heat treatment, thereby providing solid solution strengthening to the matrix. In addition to its strengthening effect, Sc also improves the material's internal deformation coordination. This is primarily because Sc agglomerates at the Al₂Cu precipitate interface, providing thermal stabilization, and forms a bidirectional coherent Al-Sc interlayer at the AlCe eutectic interface, improving the coordination of dislocation deformation in the matrix and enhancing the material's strength, toughness, and thermal stability.

[0022] Furthermore, the rare earth elements Ce and Sc, along with Ti, Zr, Mn, and V, interact to enhance the overall mechanical properties of the material. Specifically, by adding alloying elements such as Ti, Zr, Mn, and V to the aluminum-copper alloy, a certain amount of Ce and Sc is added. During the alloy melt and solidification process, precipitates such as Al3Ti, Al3Zr, and Al6Mn are formed. These precipitates can suppress dislocation movement and hinder grain boundary slip. In particular, fine precipitates play a very important role in the strength of the material. Meanwhile, a small amount of unreacted Ti and Zr phases are distributed in the matrix in the form of small rods (the unreacted Ti and Zr referred to here means that incompletely dissolved Ti and Zr will aggregate and be distributed in the matrix as small rod-shaped phases). The addition of rare earth elements Sc and Ce not only effectively inhibits the agglomeration of precipitates and increases the nucleation rate and nucleation rate of heterogeneous nucleation, thus refining the grains, but also improves the compositional supercooling of the high-strength aluminum-copper alloy melt. During heat treatment, the rare earth elements refine and even change the morphology of the precipitates, and to some extent reduce their size, transforming bulk alloy phases into short strips or rods. This reduces stress concentration and thus reduces the cutting effect on the matrix, effectively improving the microstructure refinement and enhancing the overall mechanical properties of the material. Furthermore, in addition to forming a large amount of AlCu(Sc, Ce) phase during solidification, the small amount of dispersed ternary phase AB(Ti) in the alloy is also reduced. x Zr 1-x It will undergo a phase transition, transforming into Al3(Sc) x Ti y Zr 1-x-y Furthermore, the number of dispersed phases increases with the increase of rare earth elements, and the increase in the number of precipitated phases can promote the nucleation of θ' phase during aging, thereby improving the age hardening effect of the alloy. At the same time, dispersed ternary phases are less prone to agglomeration and growth at high temperatures than binary phase particles, thus extending the holding time of the alloy at high temperatures, significantly increasing the recrystallization temperature of the alloy, thereby reducing the hot cracking tendency of the alloy and improving the high-temperature performance stability.

[0023] In a preferred embodiment, the high-strength aluminum-copper alloy has a yield strength greater than 420 MPa, a tensile strength greater than 490 MPa, and an elongation greater than 5% at room temperature; and a yield strength greater than 250 MPa, a tensile strength greater than 315 MPa, and an elongation greater than 9.5% at a high temperature of 200°C.

[0024] Another aspect of the present invention provides a method for preparing the above-mentioned high-strength aluminum-copper alloy, comprising a smelting step, wherein the smelting step includes: Aluminum ingots, Cu-containing raw materials, Mn-containing raw materials, Ti-containing raw materials, Sc-containing raw materials, V-containing raw materials, Ce-containing raw materials, and Zr-containing raw materials are added to a furnace and heated to melt. After modification and refinement treatment, ultrasonic treatment is performed. After standing, differential pressure casting is performed to obtain the ingot.

[0025] The aforementioned technical solution requires ultrasonic treatment during the smelting process. Applying ultrasonic treatment to the melt generates an alternating high-frequency sound pressure field within the melt. This sound pressure field leads to the formation of air bubbles. These cavitation bubbles, generated by the sound pressure, are subsequently subjected to intense compression and collapse. The moment of bubble collapse generates a localized high-pressure shock wave, which melts or even shatters growing crystals, inhibiting the growth of coarse grains. Simultaneously, these crystal fragments, under the influence of ultrasonic flow, accompany the melt and eventually become uniformly distributed within the melt, increasing the number of nuclei. This enhances the convection of hot melt between melts, reduces the temperature gradient between different parts of the melt, and makes the temperature field more uniform, effectively reducing defects such as porosity, gas bubbles, and component segregation. Specifically, the role of ultrasonic treatment in this application is as follows: The effect of ultrasonic treatment on porosity in castings: During the casting process of this high-strength aluminum alloy, a large number of porosity defects appear in the castings. This is mainly because the high-strength aluminum-copper alloy contains a relatively large number of alloying elements, resulting in a wide solidification temperature range and poor alloy fluidity. Since most of the gas in the aluminum alloy body is gas, when the high-strength aluminum alloy melt is ultrasonically treated, the gas present in the melt will become cavitation bubbles under the action of alternating sound pressure fields. The cavitation bubbles will continuously expand and contract under the alternating action of ultrasonic sound pressure radiation force, and the gas dissolved in the melt will be promoted by the micro-jet and acoustic flow effect generated by the ultrasound to diffuse to the interface between the aluminum melt and the cavitation bubbles and expand. Subsequently, the air bubbles that adsorb hydrogen will adsorb each other and agglomerate into larger bubbles, which will eventually float to the surface of the melt and overflow, thereby greatly reducing the occurrence of porosity defects in the castings. The effect of ultrasonic treatment on the solidification structure of high-strength aluminum alloys: In this study, the cavitation effect generated during the ultrasonic treatment of high-strength aluminum alloys improves the wettability between heterogeneous particles and molten aluminum. During ultrasonic cavitation, the collapse of cavitation bubbles generates localized high-pressure shock waves that melt and even break up growing crystals, inhibiting the growth of coarse grains. Coarse dendrites are melted or broken up under cavitation, increasing heterogeneous nucleation sites. During the solidification process of the casting, feeding becomes easier, greatly reducing the occurrence of casting defects such as porosity and shrinkage cavities caused by untimely feeding. Simultaneously, it enhances the convection of hot melt between melts, reduces the temperature gradient between different parts of the melt, and makes the temperature field more uniform, effectively reducing defects such as porosity, gas pores, and compositional segregation. Furthermore, the precipitated binary phases such as Al3Ti, Al3Zr, and Al6Mn in the high-strength aluminum alloy, as well as the Al3(Sc) phase formed after the addition of rare earth elements, also contribute to the high-strength aluminum alloy's performance. x Ti y ,Zr 1-x-y The melting point of ternary phases increases under ultrasonic treatment, which indirectly increases the supercooling and promotes the nucleation of intermetallic compounds. On the other hand, the high pressure and micro-jet impact generated by the collapse of ultrasonic cavitation bubbles will also break up the alloy phase particles and disperse them in the matrix, thereby making the casting structure more refined.

[0026] In a preferred embodiment, the smelting step includes: Aluminum ingots, Cu-containing raw materials, Mn-containing raw materials, Ti-containing raw materials, Sc-containing raw materials, V-containing raw materials, Ce-containing raw materials, and Zr-containing raw materials are added to a furnace and heated to melt. The temperature is raised to 730-740℃, and the mixture is stirred for 5-10 minutes before adding a modifier for modification treatment. Then, the temperature is raised to 740-750℃, and argon gas is used for rotary degassing. After degassing, the mixture is allowed to stand for 3-5 minutes, and after removing the slag, a refining agent is added for refining treatment. The mixture is then stirred for 1-5 minutes, allowed to stand for 3-5 minutes, and then ultrasonically stirred for 10-15 minutes. After standing for 10-20 minutes, differential pressure casting is performed at 730-740℃ to obtain the ingot.

[0027] In a preferred embodiment, the frequency of the ultrasonic treatment is 15-30 Hz.

[0028] It is important to note that the choice of ultrasonic treatment frequency directly determines the mechanism and effect of ultrasonic energy in the alloy melt. The two major effects of ultrasound in the melt (i.e., cavitation and acoustic flow) are significantly affected by frequency. Lower frequencies result in longer ultrasonic cycles and stronger cavitation. Strong cavitation leads to violent splashing and tumbling on the melt surface, greatly increasing the contact area between the melt and air, leading to gas entrapment and oxide inclusions, thus reducing the quality of the melt and the casting. Conversely, excessively high ultrasonic frequencies require higher minimum energy to generate cavitation. Under the same input power, high-frequency ultrasound struggles to generate effective cavitation bubbles, or produces fewer bubbles with lower energy. Since grain refinement and efficient degassing mainly rely on the enormous energy generated by cavitation bubble collapse, if the cavitation effect is weakened, the grain refinement effect produced by ultrasonic treatment will be significantly reduced. Moreover, the higher the ultrasonic frequency, the faster the attenuation in a relatively viscous melt like aluminum-copper alloy, and the worse the penetration ability. Ultrasonic treatment is difficult to effectively transmit to the entire melt, resulting in the inability to penetrate and break dendrites and oxide films in the melt, making it difficult to achieve the effect of refining and purifying the melt.

[0029] In a preferred embodiment, the refining agent is an AlTi5B1 master alloy.

[0030] The aforementioned technical solution limits the types of grain refiners because the core function of Al5TiB is as a heterogeneous nucleating agent, providing a large number of dispersed particles that can serve as nuclei for α-Al grains during alloy solidification, thereby significantly refining the grain structure. In this high-strength aluminum-copper alloy, the addition of Zr mainly achieves dispersion strengthening by forming Al3Zr particles. If another common grain refiner, Al-Ti-C, is used, the TiC particles will react with Zr to form more stable ZrC. This consumes the nucleation core TiC, causing the grain refinement effect to quickly fail; this phenomenon is called "Zr poisoning." However, when using AlTi5B as a grain refiner, TiB2 has much higher chemical stability than TiC and will not react with Zr. Therefore, in Zr-containing aluminum-copper alloys, the grain refinement effect of AlTi5B is more stable and durable. Moreover, AlTi5B has good compatibility with Cu in aluminum-copper alloys, enabling it to maintain good chemical stability and nucleation activity in the alloy.

[0031] Furthermore, the amount of AlSr10 master alloy added (based on Sr content) is 0.04% to 0.08% of the mass of the high-strength aluminum-copper alloy raw material; The AlTi5B1 master alloy is added at a rate of 0.2-0.9% of the mass of the high-strength aluminum-copper alloy raw material. The main function of AlTi5B in the aluminum-copper alloy is to refine the grains through heterogeneous nucleation of the TiAl3 phase and TiB2 particles. Insufficient addition results in insufficient heterogeneous nucleation sites and a weak grain refinement effect. Excessive addition leads to copper adsorption on the surface of TiB2 particles, reducing their activity as a nucleation substrate, due to the high copper content of the aluminum-copper alloy. Simultaneously, excessive titanium content results in the formation of coarse TiAl3 phases in the matrix, which can fragment the matrix and reduce the overall performance of the alloy.

[0032] In a preferred embodiment, the Cu-containing raw material is an AlCu master alloy and / or pure copper; The Mn-containing raw material is an AlMn master alloy and / or pure manganese; The Ti-containing raw material is an Al-Ti master alloy and / or pure titanium; The Sc-containing raw material is an Al-Sc master alloy and / or pure scandium; The V-containing raw material is an Al-V master alloy and / or pure vanadium; The Ce-containing raw material is an Al-Ce master alloy and / or pure cerium; The Zr-containing raw material is an Al-Zr master alloy and / or pure zirconium.

[0033] In a preferred embodiment, the Cu-containing raw material is an AlCu50 master alloy; the Mn-containing raw material is an AlMn10 master alloy; the Ti-containing raw material is an AlTi4 master alloy; the Sc-containing raw material is an AlSc2 master alloy; the V-containing raw material is an AlV4 master alloy; the Ce-containing raw material is an AlCe10 master alloy; and the Zr-containing raw material is an AlZr4 master alloy.

[0034] The above technical solution limits the source of raw materials for each metal element because (in actual production, the selection is mainly based on the effect of addition to the melt and production cost. From a metallurgical point of view, the higher the content of the master alloy, the more controllable the dissolution process and the more uniform the component dispersion in the matrix. Taking AlCu50 as an example, compared with AlCu20, AlCu50 does not melt immediately after being added to the aluminum melt, but exists in solid form. Copper atoms dissolve into the aluminum melt slowly and uniformly through solid diffusion. This slow dissolution process can be fully diffused throughout the smelting process, effectively avoiding casting defects such as component segregation caused by excessively high local concentrations. In addition, the higher the content of the master alloy, the less it needs to be added, and the fewer impurities introduced. This is particularly important for achieving precise component ratios in the alloy melt and controlling production costs).

[0035] In a preferred embodiment, the preparation method further includes solution treatment and aging treatment of the ingot; The solution treatment conditions are as follows: the solution treatment temperature is 530-540℃, the solution treatment time is 16-20h, and then quenching is performed in water at 40-60℃. After quenching, leave the product in air for 12-25 hours, then perform an aging treatment. The conditions for the aging treatment are: aging temperature of 150-160℃ and aging time of 6-10h.

[0036] It should be noted that for aluminum-copper alloys, after solution treatment and rapid quenching, the supersaturated vacancies at high temperatures are "frozen" in the alloy. These supersaturated vacancies have extremely high energy and are "high-speed channels" for the diffusion of solute copper atoms during the subsequent aging process. If the time between quenching is too short and the internal temperature of the casting is not yet uniform, the high concentration of vacancies will not be fully diffused in the matrix. At this time, aging treatment will cause the solute copper atoms in the aluminum-copper alloy to aggregate and segregate to form coarse phases, and may even cause grain boundary corrosion, thereby forming casting defects and reducing the performance of the alloy. Quenching generates significant internal stress. Aging within a short time, under high internal stress conditions, allows for atomic diffusion and phase transformation, increasing the risk of product deformation. Proper placement can allow for a degree of natural stress relaxation. However, if the quenched material is left in air for too long, the supersaturated vacancies acquired after quenching become unstable at room temperature. If the interval is too long, these vacancies will migrate to grain boundaries, dislocations, or other locations and disappear. During artificial aging, the diffusion rate of solute copper atoms drops sharply due to the significant reduction in "high-speed channels" (vacancies). This causes effective copper atoms to preferentially accumulate on a few nuclei and grow, forming coarse equilibrium phases. The precipitation strengthening effect is greatly reduced, and the aged strength decreases significantly. Therefore, selecting an appropriate placement time for aging treatment is crucial for the performance of aluminum-copper alloys.

[0037] The above technical solution specifies the exact parameters for solution treatment and aging. The reason for choosing a solution temperature of 530-540℃ is that the eutectic temperature (i.e., solidus temperature) of aluminum-copper alloys is approximately 548℃. If the temperature is too high, localized melting of the alloy will occur, resulting in overheating, an irreversible and fatal defect that drastically reduces the strength and toughness of the aluminum-copper alloy. If the solution temperature is too low, the solubility of the non-equilibrium eutectic phase CuAl2 in the matrix will also be greatly reduced. The essence of solution treatment is to allow copper atoms to dissolve from the CuAl2 phase and diffuse into the aluminum matrix to form a supersaturated solid solution. However, atomic diffusion in the solid state is a very slow process. During the solidification process of aluminum-copper alloy castings, due to the relatively slow cooling rate, the copper alloy forms coarse, network-like, or unbalanced CuAl2 phases. These phases are relatively large and difficult to dissolve in a short time. The chosen aging time of 16-20 hours provides sufficient time for copper atoms to completely dissolve from these coarse second phases and diffuse into the matrix, eliminating micro-compositional fluctuations in the casting and achieving compositional homogenization in thick castings. The aforementioned aging temperature and time are selected to obtain the optimal precipitation strengthening effect. Under these temperature conditions, vacancies and copper atoms possess just the right diffusion capacity, promoting the rapid aggregation of solute copper atoms and forming a large number of dispersed, fine metastable transition phases in the aluminum matrix. These transition phases maintain a coherent relationship with the matrix and can produce significant lattice distortion, effectively hindering dislocation movement and achieving a good precipitation strengthening effect, while simultaneously preventing the rapid transformation of the AlCu2 transition phase into a coarse equilibrium phase. Choosing an aging time of 6-10 hours is beneficial because if the time is too short, the precipitates will not have enough time to grow to the optimal size, resulting in too small and insufficient precipitates and inadequate precipitation strengthening. On the other hand, if the aging time is too long, the unstable transition phases will begin to transform into stable phases and gradually coarsen, thus preventing the alloy properties from achieving the strengthening effect of peak aging.

[0038] In another aspect, the present invention provides the application of the above-mentioned high-strength aluminum-copper alloy in the field of aviation or naval equipment.

[0039] To provide a clearer and more detailed description of the high-strength aluminum-copper alloy, its preparation method, and its applications provided by the embodiments of the present invention, the following description will be based on specific embodiments.

[0040] Example 1: Preparation of high-strength aluminum-copper alloy 1. Raw material composition (mass percentage): Cu: 4.9%, Mn: 0.65%, Ti: 0.35%, Sc: 0.4%, V: 0.3%, Ce: 0.23%, Zr: 0.22%, with the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted using a crucible resistance furnace. After all the aluminum ingots (except for the master alloy, the rest of the aluminum alloy is aluminum ingot), Al50Cu, AlTi4, AlZr4, AlSc2, AlCe10, AlMn10, AlV4, etc. are melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is then raised to 745±5℃ and degassed by rotating with argon gas. After degassing, the mixture is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, the mixture is ultrasonically stirred for 15 minutes and allowed to stand for 15 minutes. Differential pressure casting is then performed at 735±5℃.

[0041] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0042] The mechanical properties of the cast test bar obtained in this embodiment were tested. The room temperature performance indicators were as follows: tensile strength (σb) was 509 MPa, yield strength (σ0.2) was 446 MPa, and elongation was 6.5%. The high temperature mechanical properties measured at 200℃ were as follows: tensile strength (σb) was 311 MPa, yield strength (σ0.2) was 268 MPa, and elongation was 10.5%.

[0043] Example 2: Preparation of high-strength aluminum-copper alloy 1. Raw material composition (mass percentage): Cu: 5.5%, Mn: 0.6%, Ti: 0.3%, Sc: 0.35%, V: 0.3%, Ce: 0.3%, Zr: 0.22%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlSc2, AlCe10, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes and then stood for 15 minutes. Differential pressure casting is performed at 735±5℃.

[0044] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0045] The mechanical properties of the cast test bar obtained in this embodiment were tested. The room temperature performance indicators were as follows: tensile strength (σb) of 525 MPa, yield strength (σ0.2) of 442 MPa, and elongation of 5.5%. The high temperature mechanical properties measured at 200℃ were as follows: tensile strength (σb) of 328 MPa, yield strength (σ0.2) of 266 MPa, and elongation of 9.8%. Figure 1 The images show the as-cast microstructure of the sample prepared in this example and the microstructure after T6 treatment.

[0046] Example 3 1. Raw material composition (mass percentage): Cu 3.5%, Mn 0.6%, Ti 0.2%, Sc 0.3%, V 0.2%, Ce 0.2%, Zr 0.1%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlSc2, AlCe10, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes and then stood for 15 minutes. Differential pressure casting is performed at 735±5℃.

[0047] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0048] The mechanical properties of the cast test bar obtained in this embodiment were tested. The room temperature performance indicators were as follows: tensile strength (σb) of 493 MPa, yield strength (σ0.2) of 424 MPa, and elongation of 6.8%. The high temperature performance indicators at 200℃ were as follows: tensile strength (σb) of 318 MPa, yield strength (σ0.2) of 257 MPa, and elongation of 10.4%. Example 4 1. Raw material composition (mass percentage): Cu 5.5%, Mn 1.0%, Ti 0.4%, Sc 0.5%, V 0.4%, Ce 0.4%, Zr 0.3%, with the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlSc2, AlCe10, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes and then stood for 15 minutes. Differential pressure casting is performed at 735±5℃.

[0049] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0050] The mechanical properties of the cast test bar obtained in this embodiment were tested. The room temperature performance indicators were as follows: tensile strength (σb) of 516 MPa, yield strength (σ0.2) of 424 MPa, and elongation of 6.3%. The high temperature performance indicators at 200℃ were as follows: tensile strength (σb) of 319 MPa, yield strength (σ0.2) of 253 MPa, and elongation of 10.8%.

[0051] Comparative Example 1 1. Raw material composition (mass percentage): Cu: 5.5%, Mn: 0.6%, Ti: 0.3%, Sc: 0.35%, V: 0.3%, Ce: 0.3%, Zr: 0.22%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlSc2, AlCe10, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is then raised to 745±5℃ and degassed by rotating with argon gas. After degassing, the mixture is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 18 minutes. The mixture is allowed to stand for 15 minutes and then cast under differential pressure at 735±5℃.

[0052] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0053] The mechanical properties of the cast test bar obtained in this embodiment were tested, and the following performance indicators were obtained: tensile strength (σb) of 488 MPa, yield strength (σ0.2) of 416 MPa, and elongation of 5.3%. The high-temperature performance indicators at 200℃ were: tensile strength (σb) of 307 MPa, yield strength (σ0.2) of 244 MPa, and elongation of 9.5%.

[0054] Figure 2 This is a micrograph of the sample prepared for this comparative example after T6 treatment, compared with... Figure 1 Comparison of microstructure images of the sample prepared in Example 2 after T6 treatment shows that the alloy grains after ultrasonic treatment are more rounded and the size is significantly finer than those before ultrasonic treatment.

[0055] Comparative Example 2 1. Raw material composition (mass percentage): Cu: 5.5%, Mn: 0.6%, Ti: 0.3%, V: 0.3%, Zr: 0.22%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes and then stood for 15 minutes. Differential pressure casting is performed at 735±5℃.

[0056] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0057] The mechanical properties of the cast test bar obtained in this comparative example were tested, and the following performance indicators were obtained: tensile strength (σb) of 467 MPa, yield strength (σ0.2) of 398 MPa, and elongation of 8.0%. The high-temperature performance indicators at 200℃ were: tensile strength (σb) of 278 MPa, yield strength (σ0.2) of 219 MPa, and elongation of 8.4%.

[0058] Figure 3 This is a micrograph of the sample prepared for this comparative example after T6 treatment, compared with... Figure 1 Comparing the microstructure photographs of the samples prepared in Example 2 after T6 treatment, it can be seen that after adding rare earth elements (Sc, Ce) in Example 2, the number of dispersed phases in the alloy increased significantly. At the same time, the addition of rare earth elements increased the heterogeneous nucleation and compositional supercooling of the melt alloy, and an adsorption layer was generated on the surface of the precipitated phase, which hindered the continued growth of grains, resulting in a more uniform and fine microstructure.

[0059] Comparative Example 3 1. Raw material composition (mass percentage): Cu: 5.5%, Mn: 0.6%, Ti: 0.3%, Sc: 0.35%, V: 0.3%, Zr: 0.22%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlSc2, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes and then stood for 15 minutes. Differential pressure casting is performed at 735±5℃.

[0060] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0061] The mechanical properties of the cast test bar obtained in this comparative example were tested, and the following performance indicators were obtained: tensile strength (σb) of 489 MPa, yield strength (σ0.2) of 413 MPa, and elongation of 8.4%. The high-temperature performance indicators at 200℃ were: tensile strength (σb) of 296 MPa, yield strength (σ0.2) of 233 MPa, and elongation of 8.9%.

[0062] Comparative Example 4 1. Raw material composition (mass percentage): Cu: 5.5%, Mn: 0.6%, Ti: 0.3%, V: 0.3%, Ce: 0.3%, Zr: 0.22%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlTi4, AlZr4, AlCe10, AlMn10, AlV4, etc. are all melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes and then stood for 15 minutes. Differential pressure casting is performed at 735±5℃.

[0063] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0064] The mechanical properties of the cast test bar obtained in this comparative example were tested, and the following performance indicators were obtained: tensile strength (σb) of 495 MPa, yield strength (σ0.2) of 424 MPa, and elongation of 8.9%. The high-temperature performance indicators at 200℃ were: tensile strength (σb) of 303 MPa, yield strength (σ0.2) of 245 MPa, and elongation of 9.2%.

[0065] Comparative Example 5 1. Raw material composition (mass percentage): Cu: 5.5%, Sc: 0.35%, Ce: 0.3%, the remainder being Al and unavoidable impurities; 2. The preparation steps for the high-strength cast aluminum-copper alloy designed according to the above composition are as follows: Step 1: The aluminum-copper alloy is smelted in a crucible resistance furnace. After the aluminum ingot, Al50Cu, AlSc2, AlCe10, etc. are completely melted, the temperature is raised to 735±5℃ and stirred for 5 minutes to perform AlSr10 modification treatment. The temperature is raised to 745±5℃ and degassed by rotating with argon gas. After degassing, it is allowed to stand for 2 minutes. After removing the slag, the AlTi5B1 master alloy refiner is added and stirred manually for 3 minutes. After standing for 2 minutes, it is ultrasonically stirred for 15 minutes. After standing for 15 minutes, differential pressure casting is performed at 735±5℃.

[0066] Step 2: The cast test bar is subjected to solution treatment and aging in a box-type resistance furnace. The solution treatment temperature is 535±5℃ and the solution treatment time is 18h. It is then quenched in a water bath at 60℃. After quenching, it is placed in air for 16h and then subjected to aging treatment in a box-type resistance furnace. The aging temperature is 155±5℃ and the aging time is 8h.

[0067] The mechanical properties of the cast test bar obtained in this embodiment were tested, and the following performance indicators were obtained: tensile strength (σb) of 446 MPa, yield strength (σ0.2) of 354 MPa, and elongation of 6.8%. The high-temperature performance indicators at 200℃ were: tensile strength (σb) of 286 MPa, yield strength (σ0.2) of 211 MPa, and elongation of 9.3%.

[0068] Figure 4 This is a micrograph of the sample prepared for this comparative example after T6 treatment, compared with... Figure 1 Comparing the microstructure photographs of the samples prepared in Example 2 after T6 treatment, it can be seen that under the conditions of adding Mn, Ti, V and Zr in Example 2, the grain size of the alloy is significantly refined. At the same time, the amount of discontinuous short rod-shaped θ phase residues precipitated at the grain boundaries is very small. This is mainly because the addition of refining elements will form a large number of heterogeneous nuclei, which can refine the coarse equiaxed crystals into fine equiaxed crystals. The addition of refining elements significantly reduces the diffusion rate of Cu.

Claims

1. A high-strength aluminum-copper alloy, characterized in that, By mass percentage, its raw materials include Cu 3.5%-5.5%, Mn 0.6%-1.0%, Ti 0.2%-0.4%, Sc 0.3%-0.5%, V 0.2%-0.4%, Ce 0.2%-0.4%, Zr 0.1%-0.3%, with the balance being Al and unavoidable impurities.

2. The high-strength aluminum-copper alloy according to claim 1, characterized in that, The high-strength aluminum-copper alloy has a yield strength greater than 420 MPa, a tensile strength greater than 490 MPa, and an elongation greater than 5% at room temperature; and a yield strength greater than 250 MPa, a tensile strength greater than 315 MPa, and an elongation greater than 9.5% at a high temperature of 200℃.

3. The method for preparing the high-strength aluminum-copper alloy according to claim 1 or 2, characterized in that, The process includes a smelting step, which includes: Aluminum ingots, Cu-containing raw materials, Mn-containing raw materials, Ti-containing raw materials, Sc-containing raw materials, V-containing raw materials, Ce-containing raw materials, and Zr-containing raw materials are added to a furnace and heated to melt. After modification and refinement treatment, ultrasonic treatment is performed. After standing, differential pressure casting is performed to obtain the ingot.

4. The preparation method according to claim 3, characterized in that, The smelting step includes: Aluminum ingots, Cu-containing raw materials, Mn-containing raw materials, Ti-containing raw materials, Sc-containing raw materials, V-containing raw materials, Ce-containing raw materials, and Zr-containing raw materials are added to a furnace and heated to melt. The temperature is raised to 730-740℃, and the mixture is stirred for 5-10 minutes before adding a modifier for modification treatment. Then, the temperature is raised to 740-750℃, and argon gas is used for rotary degassing. After degassing, the mixture is allowed to stand for 3-5 minutes, and after removing the slag, a refining agent is added for refining treatment. The mixture is then stirred for 1-5 minutes, allowed to stand for 3-5 minutes, and then ultrasonically stirred for 10-15 minutes. After standing for 10-20 minutes, differential pressure casting is performed at 730-740℃ to obtain the ingot.

5. The preparation method according to claim 4, characterized in that, The frequency of the ultrasonic treatment is 15-30Hz.

6. The preparation method according to claim 3, characterized in that, The modifier is an AlSr10 master alloy, and the refining agent is an AlTi5B1 master alloy.

7. The preparation method according to claim 3, characterized in that, The Cu-containing raw material is an AlCu master alloy and / or pure copper; The Mn-containing raw material is an AlMn master alloy and / or pure manganese; The Ti-containing raw material is an Al-Ti master alloy and / or pure titanium; The Sc-containing raw material is an Al-Sc master alloy and / or pure scandium; The V-containing raw material is an Al-V master alloy and / or pure vanadium; The Ce-containing raw material is an Al-Ce master alloy and / or pure cerium; The Zr-containing raw material is an Al-Zr master alloy and / or pure zirconium.

8. The preparation method according to claim 7, characterized in that, The Cu-containing raw material is an Al50Cu master alloy; the Mn-containing raw material is an AlMn10 master alloy; the Ti-containing raw material is an AlTi4 master alloy; the Sc-containing raw material is an AlSc2 master alloy; the V-containing raw material is an AlV4 master alloy; the Ce-containing raw material is an AlCe10 master alloy; and the Zr-containing raw material is an AlZr4 master alloy.

9. The preparation method according to claim 3, characterized in that, The preparation method further includes solution treatment and aging treatment of the ingot; The solution treatment conditions are as follows: the solution treatment temperature is 530-540℃, the solution treatment time is 10-20h, and then quenching is performed in water at 40-60℃. After quenching, leave the product in air for 12-25 hours, then perform an aging treatment. The conditions for the aging treatment are: aging temperature of 150-160℃ and aging time of 6-10h.

10. The application of the high-strength aluminum-copper alloy as described in claim 1 or 2 in the field of aviation or naval equipment.

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